Key Largo Wastewater Treatment District Board of Commissioners Meeting

Agenda Item Summary

Meeting Date: Agenda Item Number: L-1

June 5, 2018

Agenda Item Type: Agenda Item Scope: Recommended Action:

Information I Presentation Review / Discussion Discussion

Department: Sponsor:

Engineering Ed Castle

Subject:

Photovoltaic Arrays Proposal

Summary of Discussion:

A request for proposals was published for installing a shade cover over the disinfection basin using solar panels. An additive alternate for installing solar panels on the roof of the operations building was included in the RFP. Only one bid was received, from SALT, a local company headquartered in Marathon. Weiler Engineering has been working with SALT since the proposal was received in mid-March to explore cost-savings options, finding several cost-saving opportunities.

Reviewed I Approved

Operations:

Administration :

Finance:

District Counsel:

District Clerk:

Engineering:

General Manager

Financial Impact

$ 207,300.00

Expense

Funding Source:

Grant(s)

Budgeted:

Partially

Attachments

1. Memo from WEC outlining costs and benefits 2. Value-engineered cost proposal from SALT 3. Isometric drawings of CCC cover 4. Sunpower brochure

S--3/-IV

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6805 OVERSEAS HIGHWAY | MARATHON | FL 33050 TEL (305) 289-4161 | FAX(305) 289-4162

MEMORANDUM

To: KLWTD Board

From: Ed Castle, PE

Date: May 30, 2018

Re: Photovoltaic Array Proposal Update

The FY18 Capital Projects budget includes funding for covering the disinfection basins to provide protection from the sun using solar panels. A Request for Proposals (RFP) was published, with proposals due March 22, 2018. A single proposal was received from SALT, a local company based in Marathon. As previous presented to the Board, providing shade over the disinfection basins using solar panels has a number of benefits, including:

• Reduction in sodium hypochlorite consumption by preventing UV breakdown of hypochlorite to oxygen and chlorides.

• Reduction UV degradation of plastics and other materials on top of the disinfection basin, including two autosamplers, PVC conduit, hoses, etc.

• Limits growth of algae, reducing labor for cleaning and use of shock treatments of sodium hypochlorite.

• Produces electricity to offset normal operating costs. While the RFP was still active, a decision was made to allow for an additive alternate in the hope that economy of scale might make the project more attractive. The additive alternate is to install a solar array on the roof of the Operations Building. While this array would not reduce chemical costs, it would generate electricity, and due to lower height requirements, the framework would be less expensive to construct. The proposal from Salt provided for four options for covering the disinfection basin and 4 options for the solar array on the operations building roof, using foreign-made versus domestic solar panels, and with minimum and maximum coverage areas. Our analysis of the options indicates that the lower output of the foreign-made panels made that option less attractive due to the relatively high cost of the framework and electrical work. Similarly, the smaller coverage area option has lower output, again making that option less attractive. Staff is recommending that the domestic solar panels

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be used in the configurations that maximize output. This will maximize the energy output and result in a shorter payback period. WEC has been working with SALT to explore opportunities to lower costs and improve efficiencies. We have been able to reduce costs, as shown in the table below.

Solar Option Description Original Bid Price

Value-Engineered

Price

Savings

Solar Cover over Disinfection Basins $290,217 $207,300 $82,917 Solar Array on Operations Building Roof $207,293 $164,700 $42,593 Both Solar Arrays $497,510 $372,000 $125,510 We received the final value-engineered pricing and energy output rates on May 30th, a bit too late to perform a full evaluation including energy and chemical cost savings and payback periods. The results of those evaluation will be presented at the second meeting in June, at which time the item will be brought back for action. Value Engineering Changes:

• Construct framework from aluminum rather than stainless steel • Use larger domestic-made commercial-grade solar panels with a lower purchase

and installation price (with just slightly lower output, but still 25-year warranty) • Recommended an alternative manufacturer for the aluminum framework • Recommended that SALT use a subcontractor already working at Key Largo for

installation of framework and other miscellaneous work

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1 Mobilization LS 1 $ 6,000 2 Bonds and Insurance LS 1 $ 7,600 3 Provide and install PV Array Framework for CCCs LS 1 $ 112,500 4 Provide PV modules for CCCs (without sales tax, ODP) LS 1 $ 36,500 5 Install PV modules for CCCs LS 1 $ 27,700

6Provide and install Power Conditioning System for CCCs (Inverter)

LS 1 $ 9,500

7 Connection to KLWTD power grid LS 1 $ 5,000 8 Integration into KLWTD SCADA system LS 1 $ 500 9 Annual Service Contract YR 2 $ 2,000

$ 207,300 Additive Alternate Bid Item Description

to Provide PV Array for Operations Building Roof Unit Qty1A Increase in Mobilization (if any) LS 1 $ 3,300 2A Increase in Bonds and Insurance LS 1 $ 4,800

3AProvide and install PV Array Framework for Operations Bldg Roof

LS 1 $ 16,500

4AProvide PV modules for Operations Bldg Roof (without sales tax, ODP)

LS 1 $ 71,600

5A Install PV modules for Operations Bldg Roof LS 1 $ 42,800

6AIncrease size of Power Cond.Sys. to accept add. power (Inverter)

LS 1 $ 17,300

7A Increase in connection to KLWTD power grid LS 1 $ 7,700 8A Increase in integration into KLWTD SCADA system (if any) LS 1 $ 200 9A Increase in annual service contract YR 2 $ 500

$ 164,700

Deductive Bid Item Descriptionfor Allowing Use of Existing Electical Components Unit Qty

1D Use of Water Champ Conduit and Conductors LS 1 $ 4,900 2D Use of Water Champ Main Breakers in MCC2 LS 1 $ 500

$ 5,400

Key Largo Wastewater Treatment District Photovoltaic Array Project Bid Response Form (Revised in Addendum No. 2)

Item No.

Base Bid Item Description Unit Qty

TOTAL ADDITIVE ALTERNATE BID AMOUNT

Item No.

TOTAL CREDIT FOR USE OF EXISTING ELECTRICAL COMPONENTS BID AMOUNT

A+B SP P17 37.275 kWp

TOTAL BASE BID AMOUNTItem No.

A+B SP P17 73.485 kWp

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17P 

 

25 Year Combined Warranty Protect your investment

0

SunPower P-Series

Conventional Panels

5 10 15 20 25Years

Product Warranty Length

 

SunPower provides the best 25 year Combined Power and Product warranty

in the industry, providing coverage regardless of product defect or power loss.

 

75 %

80 %

85 %

90 %

95 %

100 %

0 10 15 20 25

SunPower P-Series Conventional Step Warranty

Power Warranty Length

5

 

SunPower’s Performance Series is warranted to produce more than 97% power in the first year, then declining by 0.6% per year, ending at 82.6% power after 25 years.

SPR-P17-355-COM

SunPower® Performance Series 1500 Volt panels are designed to deliver consistent performance for many

decades in advanced 1500 Volt power plant applications.

Increased Energy Production The Performance Series modules' linear shading response enables true-tracking in single-axis tracking systems, generating more energy than conventional systems that require backtracking.1

Design Tip: When modeling P-Series energy performance be sure to use linear shading losses. For

more detailed guidance please visit https://us.sunpower.com/sites/sunpower/files/media-

library/manuals/mn-sunpower-p-series-modeling-guide.pdf

Higher Efficiency The Performance Series design minimizes white space between solar cells, eliminates reflective metal lines on the cells, and lowers electrical resistance between cells, increasing efficiency compared to Conventional Commercial Panels.2

Optimized for the Oasis Power Plant From the mounting hardware, to the electrical design within the panel, to the connectors and the 1500 V rating, everything is designed as an integral part of the Oasis Power Plant.

High Reliability Innovative panel design uses flexible and redundant electrical connections between solar cells to deliver enhanced reliability.

SunPower Quality Tested to SunPower’s rigorous quality standards, and backed by the industry’s best Combined Power and Product Warranty.

High Performance & Excellent Reliability

 Datasheet

SunPower® Performance Series 1500 Volt | P17 SunPower® Performance Series 1500 Volt | P17

86

 

 

 

 

        

Electrical Data, STC3

Model SPR-P17-355-COM SPR-P17-350-COM SPR-P17-345-COM SPR-P17-340-COM SPR-P17-335-COM

Nominal Power (Pnom) 355 W 350 W 345 W 340 W 335 W

Power Tolerance +5/−0% +5/−0% +5/−0% +5/−0% +5/−0%

Efficiency 17.2% 17.0% 16.7% 16.5% 16.2%

Rated Voltage (Vmpp) 43.4 V 43.1 V 42.8 V 42.5 V 42.2 V

Rated Current (Impp) 8.18 A 8.12 A 8.06 A 8.00 A 7.94 A

Open-Circuit Voltage (Voc) 51.9 V 51.7 V 51.5 V 51.3 V 51.1 V

Short-Circuit Current (Isc) 8.68 A 8.65 A 8.57 A 8.52 A 8.51 A

Power Temp. Coef. −0.37% / ° C 

Voltage Temp. Coef. −176.5 mV / ° C −175.8 mV / ° C −175.1 mV / ° C −174.4 mV / ° C −173.7 mV / ° C

Current Temp. Coef. 3.6 mA / ° C

Maximum System Voltage 1500 V UL & 1500 V IEC

Maximum Series Fuse 15 A

Operating Condition And Mechanical Data Temperature –40° F to +185° F (–40° C to +85° C)

Impact Resistance 1 inch (25 mm) diameter hail at 52 mph (23 m/s)

Appearance Class B

Solar Cells Multicrystalline cells

Tempered Glass High-transmission tempered anti-reflective

Junction Box IP-65, 23.6 in (600 mm) cables / MC4 compatible

Weight 51 lbs (23.1 kg)

Max. Load Wind: 50 psf, 2400 Pa, 245 kg/m² front & back Snow: 112 psf, 5400 Pa, 550 kg/m² front

Frame Class 2 silver anodized; stacking pins

REFERENCES:

1 Independent Shade Study by CFV Laboratory.

2 Compared to a Conventional Commercial Panel (310 W, 16% efficient, approx. 1.93 m²).

3 Measured at Standard Test Conditions (STC): irradiance of 1000 W/m², AM 1.5, and cell temperature 25° C.

4 Type 2 fire rating per UL1703:2013, Class C fire rating per UL1703:2002 and IEC 61730.

 

Tests And Certifications

Standard Tests4 UL1703 (Type 2 Fire Rating), IEC 61215, IEC 61730 Rated to 1500 V

Quality Certs ISO 9001:2008, ISO 14001:2004

EHS Compliance OHSAS 18001:2007, PV Cycle

Ammonia Test IEC 62716

Desert Test 10.1109/PVSC.2013.6744437

Salt Spray Test IEC 61701 (maximum severity)

PID Test Potential-Induced Degradation free: 1500 V

Available Listings UL, CEC, TUV, FSEC

4X 398 mm[15.7 in]

(B)

998 mm[39.3 in]

2067 mm[81.4 in]

46 mm[1.8 in]

46 mm[1.8 in]

(C)

FRAME PROFILE

(A) CABLE LENGTH: 600 mm +20/-10 mm [23.6 in +0.8/- 0.4 in](B) STACKING PINS(C) LONG SIDE: 32 mm [1.3 in]

SHORT SIDE: 22 mm [0.9 in]

(A)

(A)

 

Read safety and installation instructions before using this product.

 

sunpower.com Document # 519601 Rev D /LTR_US

©December 2016 SunPower Corporation. All rights reserved. SUNPOWER and the SUNPOWER logo are registered trademarks of SunPower Corporation in the U.S. and other countries. Specifications included in this datasheet are subject to change without notice.

SunPower® Performance Series 1500 Volt | P17

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